1. Field of the Invention
This invention relates generally to communication systems, and, more particularly, to wireless communication systems.
2. Description of the Related Art
Wireless communication systems typically support communication over an air interface using a selected bandwidth. For example, conventional wireless communication systems that operate according to the Long Term Evolution (LTE) of the Universal Mobile Telecommunication Services (UMTS) standards and/or protocols allocate a 20 MHz bandwidth for communication over the air interface. However, there is a continuing demand for increased bandwidth and so future deployments of wireless communication equipment, including base stations and user equipment, are expected to support communication over larger bandwidths. For example, at least one planned evolution of the LTE standards and/or protocols is expected to support bandwidths of at least 100 MHz. The expanded bandwidth can be achieved by aggregating multiple component carriers, which can be allocated to the stations and/or user equipment for communication over the air interface.
The multiple component carriers can be separately and independently allocated to user equipment for communication over either the uplink or the downlink. Control information for the multiple component carriers is transmitted over a selected channel, such as a physical downlink control channel (PDCCH). User equipment, such as a handset, or mobile units use the information transmitted over the control channel to synchronize with the network and to receive other information including pilot channel information, broadcast information, paging information, and the like. Since each component carrier in the conventional multi-component communication system supports a control channel, the overhead associated with the control channels increases roughly in proportion to the number of component carriers that are allocated to the user equipment. For example, in one proposed protocol, five component carriers will be used to provide the 100 MHz bandwidth. The signaling channel overhead associated with each of these five components, reduces the bandwidth gain that results from allocating the additional component carriers to the user equipment.
In order to establish a connection over the air interface, user equipment has to determine which of the multiple component carriers have been allocated and then decode control information for the allocated component carriers. The allocated component carriers are not necessarily known to the user equipment in advance, and so, conventional user equipment perform a blind decoding of the signaling channels of all of the available component carriers for all channel hypotheses. Consequently, conventional user equipment expends a significant amount of time and processing power performing the blind decodes. For example, blind decoding of each of the associated signaling channels may require 48 decoding attempts. Thus, in a configuration of a multi-component carrier system that utilizes five component carriers each user equipment would perform 240 blind decodes in each decoding interval (48 decoding attempts/component carrier×5 component carriers=240).